Fast charger



Feb 29, 1945- a. F. w. HL-:YER ET A1.

FAST CHARGER Filed Aug. 5, 1942 4 Sheets-Sheet Feb. 20, 1945. B. F. w. HEYER ET AL 2,369,826

FAST CHARGER Filed Aug. 5, 1942 4 Sheets-Sheet 2 Feb- 20, 1945. B. F. w. MEYER ET Ar.

' FAST CHARGER 4 Sheets-Sheet 3 Filed Aug. 5, 1942- Feb. 2.o, 1945. A B, E W HEYER ET AL 2,369,826

FAST CHARGER the temperature ofthe battery.

l Patented Feb. 20, 1945 mural) STATE FAST CHARGER Benjamin F. W. Beyer, Tenaily, Clarence W. Dalsell, West Caldwell, and John W. Horton,

East Orange. N. J.

Application August 5, 1942, Serial No. 453,712

(Cl. 32o-20) 11 Claims.

This invention relates, to battery charging al1- paratus and more particularly has reference to apparatus for charging batteries `at a high rate and the control of such apparatus.

In charging batteries by the so-called fast charge method, a, current of lirom 80 to 100 amperes is passed through the same. When using such ahigh current it is important that it be immediately discontinued when the temperature of the battery has reached a value above which damage will occur. The control of the charging of the batteries may be effected by means of a thermostat having a bulb' immersed in the electrolyte of the battery'. In many linstances by the time the battery has reached the temperature above which `damage will be caused, the battery will be adequately charged and unless some means other than the mere thermostatic control is provided after the battery has cooled suiilciently to enable' the thermostatic switch to re-close, the charging will start all over again. This will result in a waste of current and will not serve any useful purpose.

- -Moreoven when charging batteries at such a lhigh rate.any short circuit will cause considerable damage to the charging equipment unless some-protective devices are used.

vAnobllect of this invention is to provide a control mechanism for battery charging apparatus.

.Y .Another object of this invention is to provide a Vbattery charger in which a' contactor is pro- -vided in the alternating current circuit and is controlled byan-actuator energized by the battery to be charged.

A further object-of this invention is to provide a battery charger in which a contactor is provided in the alternating current circuit and is adapted to be closed by an actuator energized by the battery under charge and which is controlled by a thermostatic switch responsive to Still another object of vthis vinvention is Atc provide a battery charger having ve. contactor in the alternating current circuit thereof, a control circuit energized by the battery under charge,

and means in said control circuit for closing said contactor and means responsive to an overload onthe chargerlfor opening said contactor.

A still further object of this invention .is to provide an indicator associated with the thermostatic control circuit of a battery charger to indicate the position of the thermostatically actuated switch.

I An additional object of this invention is to 'provide a battery charger having a contacter inthealternating current circuit thereof a con- -itroLcircuit including means energized by the battery'for actuating the contactor, and signal means for-indicating whether the contactor is open or cloned.

This invention has as another object the provision in a battery charger of a contactor in the alternating current circuit, means actuated by the battery for closing said contactor, and means for closing the circuit normally closed by the contactor when the battery Iis, dead.

It is also an object of this invention to provide a resistance in series with the primary winding of the transformer of a fast charger to en;- able a slow charge to be made.

Yet another object of' this invention is to provide cooling means for reducing the temperature of the rectifier to enable a rectifier of small size to be used for charging batteries at a high rate.

With these and other objects in view which will appear more fully hereinafter, the invention resides in the apparatus and circuits lillustrated ing specification.

In the drawings:

Figure 1 is a schematic view of the circuit of a :fast charger embodying the concepts of the present invention.

Figure 2 is a view similar to Figure 1 illustrating a modined form of circuit.

Figure 3 is another view similar to that of Figure 1 illustrating a still further modled form of circuit.

Figure 4 is another view similar to that shown in Figure 1 in which means are able a dead battery to be charged.

Figure 5 is still another view similar to that illustrated in Figure 1 of the drawings and including means for cooling the rectifier so that the efilciency thereof will be increased.

In Figure 1 of the drawings there is shown `a schematic diagram of a circuit embodying the principles of the present invention. As illustrated, the charger circuit includes a transformer i having a core, lsecondary winding S. The primary winding P is tapped at a plurality -ov! points adjacent one end thereof and the leads from the taps are connected to contact points 2 of a control switch which has a selector arm 3. One wire 4 of an A. C. line is connected to the switch arm 3 and the other wire l is conected to one terminal 8 of an A. C. contactor. A conductor lextends from the movable element 1 of the A. C. contactor to the non-tapped end of the primary winding P of the transformer. 1

Thus, by means of the control switch 2, 3 and the A. C. contactor l, 1, the primary of the trans# former may be connected to, or disconnected from, the A. C. line. With this arrangement thel primary circuit is controlled by the switch y 2, 8 and the A. C. contactor l, 1.

provided to enrectifier Il. From the mid-point of the secondary winding S a conductor l2 extends to an ammeter I3 and from the latter conductor It extends and is connected by a suitable connector to one terminal of a battery I5 to be charged.

The cathode of the rectifier is connected by conductor I6 to the other terminal of battery i5 by a suitable connector.

Charging oi' a battery may be effected with apparatus connected as described, but for fast charging of batteries with currents as high as 100 amperes it is-necessary to provide for accurate control of the apparatus to obtain eilicient charging without damage to the battery or charging equipment.

For this purpose the present invention provides a control circuit associated with the charging apparatus. In this connection it will be noted that the A. C. contactor includes an actuator for the movable elernent 'l which is provided with a winding il. Winding il is connected by a conductor lc to one terminal of a thermostatic switch lb, the temperature responsive element of which is adapted to be placed in the electrolyte of the battery so that the thermostatic switch will open when the temperature of the battery exceeds a predetermined value. The other terminal of the thermostatic switch is connected by a conductor 2U to the conductor it which in turn is connected to one terminal of the battery lb. The other end of the winding il of the A. C. contacter is connected by a4 conductor 2l to a contact point 2b of a selector switch which has its Selector arm 2# mounted on a shaft common to the arm t of the control switch. Arm 2@ is insulated from. the arm 3 of the control switch but has electrical contact with the conductor le so that when the arm 22 is in a position to engage contact 22 an electrical circuit will be established from one terminal of the battery lb through conductors le and 2b in and through the thermostatic switch llt, thence through conductor le to winding ll and from winding il through conductor 2l, contact point 22, switch arm 23 and through conductor lbto the other terminal of battery l5.

When the above described control circuit is completed by closure of thermostatic switch l@ and by engagement of `the arm 2t with contact point 22, current from the battery lb will ilow through the winding lll of the fr. C. contacter and sei-veto close contacts G and l.

Since the arm 3 of the tap selector switch and the arm 23 of the control circuit selector switch are mounted on a common shalt for simultaneous movement', it will be appreciated that by moving the arm 3 into engagement with the contact 2 oi the first tap of the primary or the transformer, simultaneous engagement will be effected by the arm 2t with contact 22. The battery being .at a fairly low temperature, the thermostatic switch l will be closed and current from the battery will serve to close the A. C. contacter t, l. Thus, the primary circuit of the transformer will be completed and the charger will-come into operation.

With the control circuit described, charging of the battery will proceed until the temperature thereof exceeds a predetermined value and at this point the t-herniostatic switch i@ will open, causaD ing the current bowing through tbewindinc; il to stop. Upon failure of current to flow through the winding ill, the A. C. contactor will open. either by gravity or under sprlng'action and thus charging of the battery will be terminated immodiately. Ii' no other control were provided after the battery had cooled to a value below that at which the thermostatlc switch would close, charging would start again.

In many instances when charging at the high rate employed in fast chargers, by the time the battery has reached a temperature sufllcient tc cause the thermostatic switch to open, an adequate charge of the battery will be introduced therein and further charging of the battery would be unnecessary and involve a Waste of energy. To overcome this disadvantage, the present invention embodies a lockout arrangement so that when the thermostatic switch has opened and current has ceased to flow through the winding ll, the 'circuit containing winding l1 will be broken independently of the connection between arm 23'and contact 22 and independently of the thermostatic switch. For this purpose, a contactor having a fixed contact 24 and a movable element 25 is provided. The movable element is tied to the movable element l of the A. C. contacter and is adapted to be actuated therewith by means of the actuator which is energized by the winding lll. Fixed contact 24 is connected by a conductor 26 to a conductor 2l and the movable element is connected by conductor 2l to an elongated arcuate contact 28 with which the arm 23 of the selector switch is to engage.

Contacts 22 and 28 are close enough togethei so that the wiper element on the end of switch 23, in being moved from the contact 22 to contact 28, will maintain engagement with contact 22 until after it has engaged Contact 2b. It is important, however, that the' extent of contact 22 and the spacing between the two contacs be suirlcient that the arm 23 may be engaged with contact 22 without touching contact 'in starting acharger having circuits as described in connection with Figure l, the control switch is first moved to a position in which switch arm 3 will engage the rst tap contact 2 and switch arm 2a will engage the contact 22. With the control switch in this position and the battery clips connected to the terminals of the battery to be charged, acurrent will be caused to iiow through the control circuit as hereinbefore described and will cause the winding il' to become energized which will actuate the A. C. contactor to cause the movable contacter E to engage the first contact ti and likewise will cause the movable contact 2li to engage the xed contact 2t. After closing of the n. C. contactcr l, charge will begin to flow through the battery. ln order to increase the charging current, the control switch -is moved from the first tap contact v2 to successive tap contacts which progressively cause the charging current to be increased.

During the movement of the control switch tc -cause the arm 3 to engage successive tap contacts a, the connection between arm 23 and contact 22 will be broiren, but beforethe control circuit including the battery, thermostatic switch, and winding il is broken, it will be re-established by yengagement of arm 23 with the arcuate contact 2d. Under these circumstances the current will ilow from the battery through conductors ill and 2li to thermostatic switch le, from this switch through conductor i8 to winding Il. from wind ing il through conductor 2e to nxed contact 2li. From the nxed contact 2d the current will flow to the movable contact 25 and from there through conductor 2l to the arcuate Contact 28 which engages the end of arm 23 and from arm 23 to conductor i6 baclr to the battery.

When the control circuit is completed by engagement of contacts 2t and 2l, the battery beasoman comes suiciently charged to cause the same to heat up to a predetermined temperature which will actuate the thermostatic switch I2, the now of current irom the battery through-the control circuit will be stopped, and this will enable the,`

winding I1 to be de-energized which will permit the movable contacts 1 and 2l to be separated from fixed contacts 2 vand 24, respectively."

Under these circumstances, if after the battery hascooled suillciently to enable the thermostatic switch l2 to re-close, the control circuit will not be completed by merely closing the thermostatic switch l because oi' the break in the circuit between the contacts 24 and 25. In view of the fact that the switch arm 23 is in engagement with the arcuate contact 22 and away from the contact 22, it will be impossible for battery current to flow through the control circuit and in order to re-start charging, it will be necessary to move the control switch back to a position in which the arm 22 engages contact 22.

It will be realized from the foregoing description that in order for the lockout switch 2l, 2S of the control circuit to be eiIected, it is necessary that the control switch be moved to a position wherein the switch arm 22 is out of engagement with the contact 22. In other words, the switch arm 2 must be moved to a position away from the initial tap contact. Ii the control switch is lett on the initial tap contact and the arm 22 is left in engagement with contact 22, after the battery has been heated sumciently to actuate' the thermostat 'and has re-cooled, the l thermostatic switch will re-close and this in turn will cause the contactor 3, I to re-close, causing charging current to again be sent to the battery.

However.l in order to obtain`a fast charge'it is necessary to cause a high current to ilow through the battery and to accomplish this the control switch must vbe moved to -a position in which the arm 2 is in engagement with one ofthe tap contacts remote from the end of the primary winding.

In Figure 2 oi' the drawings, a modified form of circuit has been illustrated which includes indicator means for indicating whether or not the thermostatic switch is open or closed and indicator means to indicate whether or not the lockout switch 24, 23 is open or closed. In addition, the circuit shown in Figure 2 embodies `an overload relay which is operative upon excessive current flowing through the battery charging circuit to break the control circuit which in turn will stop the iiow of current through thebattery.

As illustrated, an indicating device 2l is incorporated in an indicator circuit including the l thermostatic switch 'l2 and the battery I3 under charge. 'I'he indicator 22 which may be in the f orm oi a-lamp which will be illuminated under thefvoltage oi' the battery being charged is con-.-

nected by a conductor 2l with one oi the leads I3 extending between the battery andl the rectier. The other side of the indicator 22 is connected. to the terminal of the thermostatic switch I9 which is remote from the conductor 2li which serves to connect the thermostatic switch to the lead Il, which is connected to the terminal of the battery. When the thermostaticswitch I2 lis closed the circuit between the battery I5A and the indicator 22 will be completed and when the thermostatic switch I2 is open this circuit will be broken.

The signalling vdevice to indicate 'whetherI the lockout switch 2l, 2l is open or closed includes a ilxed contact 22 which is positioned to be en gaged by the movable contact 2l when separated from the iixed contact 24. A conductor 22' cxtends between the iixed contact 22 and an indieating device 22 which may take the form of a bell or lamp. Another conductor connects the other terminal oi' the indicator device 22 with the conductor Il which serves to connect the secondary winding with the battery I5.

With the indicator device 22 connected as described and with the control switch in a position whereby the arm 22 is in engagement with the arcuatev contact 2l. any break in the control cir-` cuit such as the opening of the thermostatic During charging of batteries, it frequently happens that a short circuit develops in the battery and this will cause an excessive current to ilow through lthe transformer and charger circuit. Other conditions may occur in which the charger is overloaded. Since the control circuit described will be broken only by opening of the thermostatic switch I2, it is desirable to incorporate an overload relayin the control circuit. For this purpose, a relay having a ilxed contact 2l and a movable contact 2B is interposed in the conductor I8 of the control circuit between the thermostatic switch I2 andthe winding I'I. A

. winding 21 oi' the device for opening the. contacts 25 and 23 is interposed in the conductor i4 between the rectiiler and the ammeter. This winding may be positioned, however, at any point in conductors I4 or I6 of the secondary circuit and as a matter of fact may be located in the primary circuit of the transformer. Winding 21 is'so constructed that when the current passing therethrough exceeds a predetermined value, the contacts 2l and 2l will be separated. Upon separation of contacts 25 and 2B, the control circuit will be broken and A. C. contactor 8, l will open. Il' the control switch is in the first position in lwhich arm 22 engages contact 22. shutting oi! vthe power will enable contacts 35 and 2O to re-close and re-energize the control circuit.

When the control switch is in some position other than the iirst so that the arm 23 engages contact 23 and the relay contacts 25` and 36 are separated. due to opening of lockout contacts Gli 2l andl 2l the control circuit will remain open until the control switch is moved back to nrst position and arm 22 is engaged with contact 22 to by-pass the lockout switch 24, 25 even though contacts 2l and 22 be re-closed. This is of considerable advantage in that once the overload takes place, the charging current is discontinued at the A. C. source and cannot be re-started except by repeating the starting procedure, that is by moving the control switch baci:` to its first position. 'It the overload still remains, the charger cannot be started. This feature.v is of im.. portance and is very desirable in that damage to the apparatus is avoided.

In many instances, particularlyin charging new batteries or in finishing the charging of the battery. it is desirable that the charge be sent contact 4| which 42 to conductor 8.

through the battery at a low rate. For this purpose, the present invention comprehends the provision of means such as a resistance element that the amount ci current which will flow through the secondary circuit of the transformer as rectified current will be of the order of about l to 15 amperes. As shown in Figure 3 of the drawings, such a resistance which is' indicated by reference character 38, is interposed between the ilrs't tap contact 2 and the end of the primary winding of the transformer. Whenthe resistance 38 is interposed between the first tap contact and the end of the primary of the transformer this resistance will be placed in series with the primary of the transformer at the same vtime that the switch arm 23 of the selector switch is in engagement with the iirstcontact point 2. By interposing the resistance in series with the primary of the transformer, a low voltage will be produced in the secondary of the transformer and a low charging current will now through the battery.

When the resistance -38 is in series with the transformer winding, the switch arm 23 engages the contact 2d, 25 is by-passed so that even if A.a break occurs in the control circuit the automatic lockout switch lwill not prevent automatic reclosing of this circuit.' Under these circumstances the charge will be continued to be passed through the battery by re-closing the control circuit at the point where the break occurred. In view of the fact, however, that the thermostat cannot operate even if placed in the battery, which is not the case when using the slow charge because the lowered rate of 'charge cannot raise the temperature of the battery to the operation point of the thermostat Iwhich is generally 120 to 130 F., there is l .no need of the automatic lockout switch. Furthermore, lin the event of a short circuit occurring between the charging clips, only about to 25 amperes will pass through the secondary circuit 22 and the automatic lockout switch aecasac l insufficient energy to actuate the A. C. contactor,

yin series with the primary of the transformer so Y and under these conditions the overload relay will not operate, and again there is no need for the automatic lockout device.

When the control switch is moved to a position whereby the resistance 38 is cut out oi' series with the primary winding of the transformer and the switch arm 23 is brought into engagement with contact 28, the automatic lockout will again come into operation and the battery can be safety charged at the high rate.

In the circuits described and illustrated in Figi ures `l to 3 of the drawings, the battery to be charged to have some energy therein in order to energize the control circuit and to move the A. C. contactor 8, 1 to a closed position. In some instances, however, the battery will be discharged to such an extent that it will be incapable of energizing the control circuit suiciently to actuate the A. C. contactor to close the charging circuit. Under these condi tions, the present invention directly connecting the end of the winding of the primary of the transformer, which is normally closed by the A. C. contactor 8. 1, directly to the A. C. line. For this purpose, as illustrated in Figure 4 of the drawings, the circuit vis provided with an A. C. pickup contact which comprises a movable contact Il which is connected by a conductor 40 to conductor 5 and a ilxed is yconnected by a conductor With this arrangement when with a dead battery'having it is necessary for the charger is used provides means for 1' f stopped. This the A. C. pickup contact is closed, and after the charger is started there will be a suicient amount of energy across the terminals of the battery to sumciently lenergize the controlcircuit to move the A. C. contactor to closed position. The A. C. pickup contact is used only in starting and once the charger has been started it is opened by moving the control switch from starting to any one of its normal operating positions.

it is also within the concept of the present invention to so cool the rectifier as to obtain thev maximum emciency from the same. For this purpose a fan is provided for circulating air over the rectifier. As illustrated, the fan 4t is driven by a motor which is connnected by one lead I5 directly tov conductor c of the A. C. line and by another lead 63 to the conductor 8 which is connected to the A. C. line 5 by the A. C. contactor 8, ll. By this connection of the-fan with the A. C. line, said fan will be placed in operation `upon starting of the charger and after the charger has been shut o, the fan' will likewise be fan may be connected otherwise than as illustrated, but the connection .shown has the advantage of stopping the fan A. C. contactor t, 'l is open.

From the foregoing description, it will be appreciated that the present invention provides a novel control circuit and control mechanisms for use with fast chargers so that the fast charging apparatus may be utilized at its maximum efilciency.

I claim:

1. A battery charger comprising a transformer having primary and secondary windings, means including a contactor for connecting the primary winding to a supply circuit, a rectifier, a secondary circuit for connecting -said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having a winding, a thermostatically actuated switch responsive to the temperature of the battery, a

second contactor operable by said actuator, and

means including a control switch having a plurality of contacts so connected as to complete a series circuit through said thermostat switch, contactor actuator and battery when the control switch engages one contact and to complete a series holding circuit through said vthermostatic switch, contactor actuator, battery and second contactor when the control switch engages another contact.

2. A battery charger comprising a, transformer having primary and secondary windings, means including a contactor for connecting the primary winding to a supply circuit, a rectifier, a secondary circuit for connecting said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having a winding, responsive to the temperature of the battery. means independent of the contactor for connecting said thermostatic switch and contactor actuator winding in series with the battery in a normally closed circuit, and manually actuated means for making and breaking the connection of said actuator winding to the battery.

3. A ,battery charger comprising a transformer having primary and secondary windings, means including a contactor for connecting the primary winding to a supply circuit, a rectifier, a second when the a thermostatically actuated switch tme battery to be charged to close and maintain said contactor closed, and means responsive to rise of temperature-of the battery beyond a determined value to de-energize saidV contactor closing means and enable said contactor to open.

4. A battery charger comprising a transformer having primary and secondary windings, means including a contactor for connecting the primary winding to a supply circuit, a rectiiier, a secondary circuit for connecting said secondary winding in series with the rectier and a battery to be charged, contactor closing means energized by the battery to'be charged to close and maintain said contactor closed, means responsive to rise of temperature of the battery beyond a determined value to de-energize said contactor closing means and enable said contactor to open, and

vlock-out means to prevent automatic reclosing of the contactor upon reduction of temperature of the battery.

5. A battery charger comprisinga. transformer having primary and secondary windings, means including a contactor for connecting the primary winuding toa supply circuit, a rectifler, a secondary circuit for connecting said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having a winding, a thermostatically actuated switch responsive to the temperature of the battery, a control switch, a control circuit serially connecting said control switch, said winding and said thermostatically actuated switch across the battery, said control switch being 'closed by said actuator and opening upon cessation of current iiow through the control circuit, and means for by-passing the control switch to complete the control circuit when the control switch is open to energize said winding from the battery.

6,. A battery charger comprising a transformer having primary and secondary windings, means including a contactor for connecting the primary winding to asupply circuit, a rectiiier, a. secondary circuit for connecting said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having af winding, a thermostatically actuated Vswitch responsive to the temperature of the battery, a control switch, a control circuit serially connecting said control switch, said winding and said thermostatically actuated switch across the battery, said control switch being closed by said -actuator and opening upon cessation oi current flow through the control circuit, means for bypassing the control switch to complete the control circuit when the control switch is open and a selector switch in said control circuit operable in one position to complete the control circuit through the by-pass means and operable in another position to complete the control circuit through the control switch.

7. A battery charger comprising a transformer having primary and secondary windings, means including a contactor for connecting the primary winding to a supply circuit, a rectiiier, a secondary circuit for connecting said .secondary winding in series with the rectiiier and a battery to .be charged. an actuator for said contactor having a winding, a control circuit including the actuator winding and the battery .to be charged to causeV the battery toenergine the winding to close and maintain said actuator closed, an overload relay having contacts 'in said control circult and a winding in said secondary circuit for opening the contacts and said control circuit upon current of a predetermined value flowing in the 'secondary circuit and means responsive to rise of temperature of the battery beyond a predetermined value to interrupt said control circuit.

8. A battery charger comprising a transformer having primary and secondarywindings, means including a contactor for connecting the primary winding to a supply circuit, a rectier, a second ary circuit for connecting said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having a winding, a control circuit including the actuator winding and the battery to be charged to cause the battery to energize the winding to close and maintain said actuator closed; a thermostatically actuated switch included in said control circuit and responsive to the battery temperature for opening and closing said i circuit, and means for indicating whether th thermostatically actuated switch is closed or open.

9. A battery charger comprising a transform er having primary and secondary windings, means including a contactor forv connecting the primary winding to a supply circuit, a rectifier, a secondary circuit for connecting said secondary winding in series with the rectifier and a battery tobe charged, an actuator for said contactor having a winding, a control circuit including the actuator winding and the battery to be charged to cause the battery to energize the winding to close and maintain said actuator closed, a thermostatically actuated switch included in said control circuit and responsive to the battery temperature for opening and closing said circuit, and electrical signalling means connected to said battery through said thermostatically actuated switch for indicating whether the thermostatically actuated switch is closed or open.

l0. A battery charger comprising a transformer having primary and secondary windings, means including a contactor for connecting the primary winding, to a supply circuit, a rectifier. a secondary circuit for connecting said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having a winding connected across the battery to be charged and energized thereby.

for closing and maintaining the contactor closed, `and means manually operable for connecting the primary winding to said supply circuit inde- `lpendently of the contactor when the battery is dead.

11. VA battery charger comprising a transformi ver having primary and secondary windings,

means including a contactor for connecting the primary winding to a' supply circuit, a rectier, a secondary circuit for connecting said secondary winding in series with the rectifier and a battery to be charged, an actuator for said contactor having a winding connected across the battery to be charged and energized thereby, a resistance in series with the primary winding of said transformer. said primary winding having a plurality of taps, a resistance connected in series with the first tap ot said winding and having a tap on its free end and a selector switch cooperating with all of said taps.

' BENJAMIN F. W. HEYER.

JOHN W. HORTON. CLARENCE W. DALZELL. 

